These tennis aces are the world’s wealthiest

The U.S. Open, the Australian Open, Wimbledon, the French Open... All the tennis Grand Slam tournaments have one thing in common: with victory comes success, and with success comes wealth.

As CNBC speaks to one of the world's most successful female tennis stars, Maria Sharapova, we take a look at the sport's wealthiest players, with help of Forbes' 2014 rankings (June 2013-2014), the Association of Tennis Professionals (ATP) and the Women's Tennis Association (WTA).

For more on Maria Sharapova, check out the CNBC website and TV network, for "CNBC Meets: Maria Sharapova."

- By CNBC's Alexandra Gibbs

Born in Denmark, 24-year-old Caroline Wozniacki is in her tenth year as a professional tennis player. 

Although she has never won a Grand Slam—despite playing in the finals of the U.S. Open in 2014 and 2009—she has generated nearly $20 million worth of prize money since 2005.

In February 2015, Wozniacki signed a deal with Godiva Chocolatier, a premium chocolate business. She also has a contract with sportswear brand, Adidas.

Currently, she is fifth in the singles world rankings.

• Total Annual Earnings: $10.8 million (Forbes, June 2013-2014)
• Noteworthy wins: U.S. Open runner-up (2009, 2014)
• Country: Denmark

Japan's Kei Nishikori only turned professional in 2007 after starting up the game when he was five years old.

While Nishikori hasn't yet won a Grand Slam, he came runner-up in 2014's U.S. Open. On top of his prize winnings, which amount to $8.59 million, Nishikori is linked to popular brands including Delta Airlines, Jaguar, Tag Heuer and Wilson sports clothing.

Nishikori is currently fifth in the singles world rankings.

• Total Annual Earnings: $11 million (Forbes, June 2013-2014)
• Noteworthy wins: Japan Open 2014 and 2012 (1st)
• Country: Japan 

Not even 26 years old and Victoria Azarenka has already received more than $24.4 million in prize money. She also has famous brands behind her like Nike, Red Bull and Wilson.

In terms of Grand Slams, Azarenka won the Australian Open in 2012 and 2013. She also won the singles' bronze medal, and the mixed doubles' gold medal in the London 2012 Olympics.

• Total Annual Earnings: $11.1 million (Forbes, June 2013-2014)
• Noteworthy win: Olympics 2012 bronze medal, Australian Open 2012/2013 (1st) 
• Country: Belarus

Source: Azarenka's site

Representing the U.K., all eyes have been on Andy Murray since 2005. Not only because it was the year he turned professional—it was also when he overtook Tim Henman as the country's favourite tennis superstar.

In 2012, Andy Murray won both the London 2012 Olympics gold medal and the U.S. open. In 2013, Murray finally won Wimbledon: the first British man to win since 1936. He is currently ranked fourth in the singles world rankings.

• Total Annual Earnings: $19.2 million (Forbes, June 2013-2014)
• Noteworthy wins: Wimbledon 2013 (1st)
• Country: United Kingdom

One of the world's most famous tennis players, Serena Williams has been playing professionally since 1995, when she turned 14. Since then, Williams has won 19 Grand Slams, three of which were in 2002.

She is currently the top female tennis player in the world, and has a net worth of $100 million, according to news site "The Richest." Williams' sponsors include Wilson, OPI Products, Gatorade and Nike.

• Total Annual Earnings: $22 million (Forbes, June 2013-2014)
• Noteworthy wins: Olympics 2012 Gold medal, 2014 U.S. Open (1st)
• Country: United States of America

Source: Serena Williams' site, The Richest.

Li Na has represented China since she turned professional in 1999, and has captivated fans as both a singles and a doubles competitor. 

She has won two Grand Slam titles in her career: the Australian Open in 2014 and the French Open in 2011.

In September 2014, Li Na retired as an athlete after a persistent knee injuries caused her to step down. During her career, she won over $16.7 million in prize money. 

• Total Annual Earnings: $23.6 million (Forbes, June 2013-2014)
• Noteworthy wins: Australian Open 2014 (1st)
• Country: China

The world's highest-paid female tennis player is none other than Maria Sharapova. The Russian-born athlete, who's been playing tennis since she was four years old, is ranked second in the singles world rankings.

But it's not all about tennis for Sharapova, who founded the candy brand Sugarpova in 2012, which reflects her "fun, fashionable, sweet side," according to its website. 

A percentage of sales go to Sharapova's charity, the Maria Sharapova Foundation. She also became a United Nations Development Program Goodwill Ambassador in 2007.

• Total Annual Earnings: $24.4 million (Forbes, June 2013-2014)
• Noteworthy win: French Open 2012 (1st) 
• Country: Russia

Source: UNDP.org.  

Serbian-born Novak Djokovic is currently the world's highest-ranked male tennis player, and has been since 2011. 

Born in 1987, Djokovic turned pro in 2003, but really grabbed the world's attention in 2008, when he won his first Grand Slam in Australia. He kept flourishing into 2011, when he won three out of four Grand Slams.

Currently, Djokovic is ranked 17th among the world's wealthiest athletes and was featured in TIME Magazine's list of the most influential people in 2012. In terms of sportswear, Djokovic signed an endorsement deal with Uniqlo, a Japanese fashion brand, in 2012.

• Total Annual Earnings: $33.1 million (Forbes, June 2013-2014)
• Noteworthy win: Australian Open 2015 and 2013 (1st)
• Country: Monaco, Serbia

Source: Novak Djokovic website.

He might be only 28 years old, but Rafael Nadal is currently the world's ninth-wealthiest athlete—a figure helped by the $14.5 million in prize money he won between June 2013 and June 2014, according to Forbes.

After turning pro when he was only 15, Nadal took the world by storm in 2005 when he won the French Open, which he has won every year since, except from 2009 when Roger Federer took the crown.

Outside his tennis career, Nadal has been the face of many brands, including Nike, Bacardi, and luxury designer brand, Armani.

• Total Annual Earnings: $44.5 million (Forbes, June 2013-2014)
• Noteworthy win: French Open 2012 - 2014 (1st)
• Country: Spain

It might come as no surprise that, after 17 years in the business, Roger Federer is the world's wealthiest tennis player.  

Between 2004 to 2007, Federer was the world number one—a title he took back again in 2009. 

Federer has won 17 Grand Slams and 84 singles titles during his time as a professional sportsman. His best Grand Slam performance has been at Wimbledon, which he has won seven times.

With an estimated net worth of $300 million, Federer is never far from the spotlight. The player has been the face of numerous luxury brands, including Moet & Chandon champagne, Rolex watches, and NetJets, a private aviation company.

• Total Annual Earnings: $56.2 million (Forbes, June 2013-2014)
• Noteworthy wins: 7 Grand Slam wins at Wimbledon (2003-2007, 2009, 2012)
• Country: Switzerland

Source: Roger Federer's official site, The Richest,